1. Field of the Invention
The present invention relates generally to bracket means for connecting the side sections of an annular frame and more particularly to bracket means for connecting the mitered corners of an annular frame.
2. Description of the Prior Art
Frames, such as are commonly used with paintings, needlepoint, or the like, are frequently made with mitered corners. Normally, on prefabricated frames, there is little need for the user to be concerned about the squareness of the corners since the miters can be made fairly accurately with conventional, production machinery. Only if the frame is in need of repair will there be any problem with maintaining the corners perfectly square. However, there is a large market for "do-it-yourself" frames wherein the side sections of the frame are secured to each other by the ultimate user who may not have sufficiently accurate equipment for making a perfectly square corner. Accordingly, there is a substantial need for a low cost, simple yet effective bracket that will assure a perfectly square corner for a frame, particularly, but of course not limited to those frames that are assembled by the user.
There are many examples in the prior art of brackets that are intended to assist in the formation of the corner of a frame. For example, U.S. Pat. No. 132,114 discloses an L-shaped bracket having an opening in each leg thereof, so that the bracket may be secured to adjacent sections of a frame that has a mitered corner. While the structure disclosed in U.S. Pat. No. 132,114 is perfectly adequate for its intended purpose, it will be appreciated that, if there is any inaccuracy in the mitered corner, then the frame will not be square since the bracket does not provide any means for orienting one section with respect to the other. That is, there are no tabs provided in the patented bracket with the tabs being at right angles to each other to thereby assure that the frame will be square.
U.S. Pat. No. 254,965 discloses still another corner bracket which is comprised of a first L-shaped portion defined by first and second legs and a second L-shaped portion defined by first and second legs with said first and said second L-shaped portions being at a right angle with respect to each other. The first L-shaped portion serves to join two adjacent sections of a frame while a second L-shaped portion assures that the frame sections are perpendicular to each other. Once again, the structure disclosed in U.S. Pat. No. 254,965 is perfectly adequate for its intended purpose. However, it will be appreciated that no means are provided for squaring the outside surface of the frame.
Still another example of the prior art is disclosed in U.S. Pat. No. 1,402,304. In this last mentioned patent an L-shaped bracket is provided with sharp prongs punched outwardy therefrom and with holes for receiving the shank of several screws that are used for securing the bracket to a frame. The pointed prongs are intended to bite into the frame for purposes of assuring rigidity. However, as pointed out in connection with the first described example of the prior art, no means are provided for assuring that the frame sections are perfectly square with respect to each other. That is, the bracket could be applied in a skewed condition and thus the frame will not be square if the mitered joint is not perfect. The absence of right angle tabs precludes the possibility of the bracket shown in U.S. Pat. No. 1,402,304 from squaring the frame.
In U.S. Pat. No. 2,340,924, there is disclosed a cleat that is L-shaped in one embodiment thereof and which is arranged to secure a mitered corner of the frame on the inside surface thereof. Holes are provided in the cleat for receiving fasteners that engage the frame sections and sharp pointed prongs are also provided for engaging the frame sections. It will be appreciated, however, that means have not been provided in U.S. Pat. No. 2,340,924 for accommodating the outside surface of a mitered corner. Nor in this last mentioned U.S. patent is there any means by which a second, inner frame may be automatically squared and coupled to a first outer frame.
U.S. Pat. No. 2,400,266 also discloses another cleat that is adaptable to either or both inside and outside corners of a frame. It will be noted however, that this last mentioned structure is not applicable to a mitered corner such as is normally found in a picture frame.
U.S. Pat. No. 2,519,628 discloses a corner bracket for a curtain stretcher that is similar in both construction and function to U.S. Pat. No. 254,965 discussed hereinabove and contains the deficiencies thereof. For example, in U.S. Pat. No. 2,519,628, no means are provided for engaging the inside surface of an annular frame. Nor are means provided for automatically squaring and coupling a second inner frame to a first outer annular frame.
U.S. Pat. No. 2,857,635 discloses a complex device for forming a miter joint. The structure disclosed in this last mentioned U.S. Patent requires a continuous groove in the frame for receiving the bracket and therefore is of limited applicability. In any event, no means are disclosed or suggested for engaging either the inner or the outer surfaces of an annular frame. Nor are means provided for coupling a second inner frame to an annular frame.
Finally, there is disclosed in U.S. Pat. No. 2,947,391 a device similar to that disclosed in U.S. Pat. No. 2,857,635 in that a special grooved construction is required in order for the device to be operable. Once again, no means are provided that will render the patented bracket adaptable to both the inside and outside edges of an annular frame. Nor are means taught that will permit both the squaring and coupling of a second inner frame to a first annular outer frame.